As one of the few people still in uniform to have played at RFK Stadium in its previous incarnation, Washington Nationals manager Frank Robinson has been insisting for months the place is a hitter’s park.

Two games into its revival as a major league venue, RFK is only partly living up to Robinson’s assessment.

The Nationals seem to like hitting in their new home — but they really love pitching here.

Just ask John Patterson, the second straight Washington starter to toss a gem at RFK. Two nights after Livan Hernandez’s near-shutout in the historic home opener, Patterson threw seven scoreless innings of his own last night, helping the Nationals romp to a 9-3 victory over the Arizona Diamondbacks before an enthusiastic crowd of 34,943.

It may be too early to start talking about home-field advantages, but the team without question is enjoying life in its new digs.

“I like it,” Patterson said. “The fans have been great, hearing them get excited with two-strike counts and two outs and things like that. When they come up out of their seats, that really pumps us up.”

Still aglow from Thursday night’s pageantry, the Nationals are now 2-0 at RFK, have won four straight and at 7-4 overall are back in sole possession of first place in the National League East.

“We’ve only played two ballgames here, but I’ll tell you, it’s great to play out there,” Robinson said. “[The fans] are very noisy. When you get something going, boy, they let you know they’re here. That’s a great feeling.”

Win No. 7 of the season was made possible both by Patterson’s newfound brilliance on the mound and Vinny Castilla’s continued brilliance at the plate. For the second straight game, the veteran third baseman went 3-for-3 with a home run — this one a two-run shot off Russ Ortiz (1-1) in the fourth. He has now reached base in all eight of his plate appearances at RFK, and his home slugging percentage is a ridiculous 2.667.

“Maybe he knows something about this ballpark,” Robinson said jokingly.

As was the case Thursday, Castilla got some help. Though his fourth-inning homer represented the only scoring for six innings, the Nationals padded their lead with a seven-run seventh that featured two hits by Castilla. Jose Vidro added a three-run double, and Brad Wilkerson contributed a two-run single, helping turn this game into a blowout.

“It’s not Murderer’s Row, but we have guys who get the big hit and guys who can hit the ball out of the ballpark throughout the lineup,” Robinson said. “That’s all it takes. It doesn’t take a lot of hits, as you saw tonight. It takes hits at the right time. You get people on base and you get hits at the right time, you score runs.”

Last night’s win was the Nationals’ eighth straight over the Diamondbacks (the first six coming, of course, when they were the Montreal Expos). The last time the franchise lost to Arizona, Patterson was wearing a Diamondbacks uniform.

A one-time top prospect in Arizona who never lived up to his potential, Patterson certainly has found his groove in the last week. With two starts under his belt in 2005, the 27-year-old right-hander has a 1.29 ERA with a 12/2 strikeout/walk ratio.

Patterson (1-1) was brilliant in his debut last Sunday at Florida, matching Marlins ace Josh Beckett pitch for pitch before surrendering two runs in the seventh inning. That performance earned him a more permanent place in Washington’s rotation, ahead of Zach Day, who started the Nationals’ second game of the season.

As good as he was in his first start, Patterson took it to another level last night. That much was obvious after the first inning, in which he struck out Craig Counsell and Luis Gonzalez looking — the latter leading to a strikeout-throw out double play, with catcher Brian Schneider nailing Royce Clayton at third base.

Patterson had the Diamondbacks baffled all night. In seven innings, he allowed just four hits and struck out six — all looking.

“He’s being real aggressive, not nibbling,” catcher Brian Schneider said. “He’s going right after hitters. … He’s in one of those grooves right now where he’s throwing all four pitches for strikes.”

Patterson had thrown only 88 pitches when he left the mound in the seventh and seemed ready to go back out in search of a complete game. With his team still clinging to a 2-0 lead at the time, though, Robinson elected to pinch-hit for both slumping shortstop Cristian Guzman and Patterson in the seventh. The move paid off, because the Nationals went on to send 11 men to the plate in their seven-run spree.

“I just felt like right there, it was important for us to get some runs out of that situation,” Robinson said. “You never know how many runs you’re going to need.”

Turns out he needed some of them after all. A quartet of relievers was required to close out this game, with Luis Ayala drawing the manager’s ire after allowing a leadoff walk and later a three-run homer to Gonzalez in the eighth. Neither Joey Eischen nor Day (in his first relief appearance of the year) could finish off the ninth, so Robinson was forced to summon closer Chad Cordero for the final out.